Fluid-pressure braking apparatus



Dec. 4, 19'28.

C. W. SPROULL FLUID PRESSURE BRAKING APPARATUS Filed Oct. 9, 1928Contmlladby Taffi'c Conditions L'nAdVance ToMae'n 3 ResePVo' inPosz'tzbn w .W .WM w m m7 W INVENTORI Patentecl Dec. 4, 1928.

f UNITED sTATEs PATENT OFFICE. w

('JLAIR'ENCE W. SPR-OULL, OE EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR T0THE UNION SWITCH & SIGNAL COMPANY, IPORATION OF PENNSYLVANIA.

OF SWISSVALE, IPEN'NSYLVANIA, .A COR- FLUID-'IRESSUBE BRKING APPRATU S.

Application fiiea October 9,1928 serial No, 140,451.

My invention relates to'fluid pressure braking apparatus, andparticularly to automatic brake applying mechanismj More particularly myinvention relates to means for conw trolling the automatic applicationof the brakes on a railway train. p

I will describe one form of apparatus embodying my invention, and thenpoint out the novel features thereof in claims. p

In the accompanying drawings Fig-1 is a diagrammatic view showing' oneform of fiuid pressure braking apparatus embodying my invention, thevarious valves being shown in section. Fig, 2 is a fragmentary sectionalview of the enginemanis brake valve in service position. Fig. 3 is afragmental*viewV showing one modifiCa-tion of a portion of the apparatusshown in Fig. 1.

Referring first to Fig. 1, the reference character R desi'gnates a traincarried relay which is Controlled in accordance with traffic conditionsin advance of the train. Under normal conditions with the trackway aheadof the train unoccupied, the relay is energi'zed, thus holding itscontact 7 closed. Under these conditions battery 9 supplies current towindi ing 10 of a magnet valve M, so that armature 11 of the magnetvalve M is held down against the action of a spring 12 and the pressurein Vpipe 4, thus holding,r valve 13 against the valve seat 14 and awayfrom the valvel seat 15 so that stop reservoir S is open to atmospherethrough opening 15 and port 16. v

' Themagnet valve M vserves to control the automatic 'application of thebrakes on the train through an automatic application valve A. The brakesmay also be applied manually by means of the enginemafls brake valve'B.The application valve A Comprises a valve body 17 divided into twochambers 22 'and 23 by means of a piston 19. o The piston 19 1sVarranged to operate a'lslide ualve 18, when nioved toward the leftagainst the action of spring 24. Fluid pressure is normally suppliedfrom some convenient source, such as the main reservoir, to the Chamber22 through pipe '1.` Piston 19'isprovided with aleak port 20 whichallows the pressure in Chamber .323 to build up to that of the'source 1when pipe 4 is blankedby slidevalve 18 and by valve 13. When thepressure is the same in both chambers the piston 19 is held in 'its themagnet valve M by means ofthe pipe 4 which is normally charged tomain'reservoir pressure from Chamber 23. Pipe 4 may-also be connectedwith pipe 5 by means of port 40 inslide valve 18 under certainvconditions which wlll appear herelnafter.

' Chamber 22 of valve A is normally connected, by means of pipe 6 andfeed valve 50 with the engineman7s brake valve B. Valve` B comprisesavalve seat 25, a rotary member i 26, and Va Vvalve Chamber 27. Theabutting surfaces of the valve seat 25 and rotary member 263'areprovided with valve ports, certain of which may be brought intoregistration by manipulation of'handle 28.l '1 When the brake sure tothe lower Chamber 30 of an equalizing Valve' V. Thisy valve has twochambers 30 and 31separated by a piston 32, which is nor- 'mally inV itslower position, the Chamber 31 being suppliedwith brake pipe-pressurefrom pipe 6, thro'ughfeed vvalve 50, port 29 in the e brakevalve B, pipe21, port 33 in slide valve 18, vand pipel 8. It'will thus be seen thatunder 'normal'conditins'brake pipe pressure'is supplied to both chambersof the valve V so that vent 34 is closed by plunger 35,'pi ston 32 beingI Vin its lower position.

' Brake pipe pressure is also supplied to'an 'equalizing 'reservoir Ewhich is connected with pipe 8, but the pressure in this reservoirisreduced v'whenvalve A is moved to the left vhand' position. This maybe accomplished, as? shown Zin Fig. 1,' by connecting pipe 8 throughalportz33 in the slide valve 18, a restricted orifiee 2,,and pipe 43with a reservoir Xvwhich isnormally connected with atmosphere as willbe'plain from' the drawing.

phere through lthe orifice2 instead of through this orifice intotheres'ervoir i If 'a manual service. appl'cation of the t 'i Thereduction in the. equalizing reservoir w. 'pressure may also be made asshown in Fig. 3, by venting the reservolr directly'to atmosbrakes isdesired the engineman moves the brake valve B 'to the service position(as shown in Fig. 2). This blanks pipes 3 and 6 and Connects pipe 21 toatmosphere through ports 29 and 36. The eqiualizing reservoir E andChamber 31 of equahzing valve V will be vented to atmosphere throughpipe 8, port 33 in valve A, pipe 21, and ports 29 and 36. As soon as thepressure in Chamber 31 falls below that in Chamber the piston 32 will beforced upward. Brake pipe 3 Will therefore be opened to atmospherethrough vent 34 and the brakes Will be applied. When the speed of thetrain has decreased sufliciently the en- .gineman may release the'brakesby moving the brake valve to the running position. Pressure is thensupplied to both chambers 30 and 31 of the equalizing valve V, piston 32is pushed downward by the pressure above it to close vent 34, and brakepipe 3 and equalizing reservoir E are again charged to normal pressure.The mode of operation of the apparatus during an automatic applicationis as follows:

When the relay R becomes de-energized.`

. valvei13 is pushed upwardly against seat, 15

under the actionof spring 12 and the pressure in pipe 4. Reservoir S isthen disconnected i from atmosphere, and is connected with pipe e 4, andhence With Chamber 23 of valve A. T

pressure in Chamber 23, therefore falls, and piston 19 is forced intoits left hand position 'by the pressure in Chamber 22. Slide valve 18,in moving to the left hand position conneets pipes 3 and 6 by. meansofport 42, thus Cutting ofl the supply of mainreservoir pressure to theenginemams brake Valve B and also blanks pipe 21. The same operation ofvalve A connects pipe 8 with orifice 2 so that the pressure in reservoirE is reduced. The

piston 32 of valve V, therefore rises, venting the brake pipe 3throughvent 34 in such manner that the rate of pressure reduction inbrake pipe 3 will be substaintial-ly the same as `the rate of reductionin reservoir E. If the brake pipe is in a leaky condition so that therate of pressure reduction due toleakage is greater than that at whichthe pressure is reduced in the equalizing reservoir E, the vent 34 Willnot open at all, but the hrake a plication resulting will be due solelyto bra e pipe leakage. i

In moving to the left, slide valve 18 also connects pipes 4 and 5 bymeans of port 40 so that pipe 4 and stop reservoir `S are vented toatmosphere through pipe 5, port 38 in brake valve B, and dischargeorifice 37. This prevents pressure from building up in pipe 4 ,andreturning piston 19 of valve Ato its right hand posltion without brakevalve first being moved to the lapposition.

After an automatic a plication has been made the brakes can be re easedonl after the brakevalve B has been movedto t e lap position, in whichall pipes 3, 5, 6 and 21 and also openings 36 and 37 are blanlted byrotary member 26 of valve B. The closing of orifice 37 permits pressurefrom main reservoir to gradually restore the pressure in Chamber 23 ofvalve A by building up in reservoir S and pipe 4 through leak port 20,until thepiston 19 is moved to the right by spring 24. As soon as valveA is restored to normal, valve B may be restored to running position.Main reservoir ressure is then again supplied through cham er 22, pipe 6feed valve 50 and port 29 in valve B `to rechar e brake pipe 3.'Pressure is also supplied rom port 29 in valve B, through pipe 21, port33 and pipef8 to reservoir E and Chamber 31 to restore piston 32 ofvalve V to its normal Closed position. `AsV complete a second and largerreduction is made. The shock effects due to difference in time requiredfor brake pipe reduction to take place in the two ends of along trainare thus materially reduced. i

In standard practice the brake pipe pressure is usually pounds persquare inch, and under such condition it has been found to beimpracticable to reduce the brake pipe pressure on a train of 100 carsat' a greater rate than 15 pounds from 70 pounds in approximately 25seconds, if unrea'sonablyl ,severe shocks between cars are to beavoided. I, ,therefore, propose to simplify the apparatus employed inautomatic applicationsby so proportionin the volume ofthe equalizingreservoir E an the discharge orifice 2 that the pressure in theequalizizng reservoir is reduced at approximately this rate.` In orderto accomplish a reduction of 15 pounds from 70 pounds in approximately25 seconds, I have discovered that the equalizing reservoir should havea volume between 2500 and 4300 cubic inches, if the discharge orificehas a diameter of 1/16 inch, and vents the reservoir directly toatmosphere as in Fig. 3, the exact volume depending somewhat upon thelengths of the various pipes used in the system.

With the apparatus arranged to reduce the eqnalizng reservoir pressure15 pounds in not less than25 seconds, I have found that undesirableshocks are materially reduced, and

t will t us be seen thatmy arrangement of equalizing reservoir andreduction discharge orifice accomplishes substantially the same resultsas are obtained by means of split reduction and materially simplifiesthe apparatus by eliminating the reservoirs and VValves which arenecessary for automatic split reduction.

Although I have shown and described only one form of fluid pressurebraking apparatus embodying my invention, it is understood that Variouschanges and modifications may be made therein Within the scope of theap-V pended claims without departing from the spirit and scope of myinvention.

- Having thus described my invention, what I claim is: q 1. In automaticfluid pressure braking apparatus comprising an equalizing reservoirVtion Valve, and means controlled-by said Valve for at times reducing thepressure in said reservoir at a rate not exceedingil pounds in 25seconds.

3. In combination With automatic fluid pressure braking-apparatuscomprising an equalizing reservoir normally oharged With fluid pressure,to approximately 7 O'pounds per square inch, an automatic brakeapplication valve, and means controlled' by said Valve for at timesreduoing the pressure in said reservoir to approximately pounds in atleast 25 seconds.

4. In automatic brake'applying apparatus an equalizing reservoir havinga Volume bee tween 2500 and 4300 cubc inches, means for normallycharging the reservoir With fluid pressure, an equalizing valveresponsiveto the pressure in said reservoir for controlling the pressurein the brake pipe, and means for at times discharging the reservoirthrough an orifice substantially 1/16 inches indiameter. 5. In automaticbrake applying apparatus an equalizing reservoir having a Volume between2500 and 1300 cubic inches, means for normally charging the reservoirWith fluid pressure at approximately 70 pounds per square inch, anequalzing valve responsive to the pressure in said reservoir forcontrolling the pressure in the brake pipe, and means for at timesdscharging the reservoir through an orifice substantially 1/16 inchesinl diameter. w

6. In automatic brake applying apparatus an equalizing reservoir havinga volume be'- tween 2500 and 4300 cubic inches, means for normally'charging the reservoir With fluid pressure at approximately 70 poundsper square inch, an equalizing Valve responsive to the pressure insadreservoir for controlling the pressure in the brake pipe, anautomatic brake application valve and means controlled by saidapplication Valve for at times connecting the reservoir With atmospherethrough an orifice approximately 1/16 inches in diameter.

In testimony Whereof I aflix my signature.`

CLARENOE a W. SPROULL.

